DC commutator motor and automobile including the same

Abstract

A DC commutator motor includes a yoke, a field magnet, and an armature. A shaft is positioned on a central axis of the armature. A plurality of commutator segments is positioned in a circumferential direction of the shaft. A plurality of armature slots is formed on an outer periphery of an armature core. An upper coil is wound the number of turns Na through two armature slots, which are located apart from each other with the predetermined number of armature slots therebetween, at their opening sides. A lower coil is connected in parallel with the upper coil and wound the number of turns Nb through the two armature slots at their bottom sides. The number of turns Na is smaller than the number of turns Nb.

What is claimed is: 
     
       1. A DC commutator motor comprising:
 a yoke; 
 a field magnet positioned at an inner peripheral side of the yoke; 
 an armature rotatably supported at an inner peripheral side of the field magnet with a gap therebetween; 
 a shaft positioned on a central axis of the armature; 
 a plurality of commutator segments positioned in a circumferential direction of the shaft; 
 a plurality of armature slots positioned on an outer periphery of the armature; 
 an upper coil wound the number of turns Na through two of the armature slots at an opening side of each of the two slots, the two of the armature slots being located apart from each other with a predetermined number of armature slots therebetween; and 
 a lower coil connected in parallel with the upper coil, the lower coil being wound the number of turns Nb through the two of the armature slots at a bottom side of each of the two slots, 
 wherein the number of turns Na is smaller than the number of turns Nb, and the number of turns Na of the upper coil and the number of turns Nb of the lower coil are set such that a lower coil resistance value is higher than an upper coil resistance value, 
 wherein 
 an end point of winding of an i-th (where i=1 to N) upper coil is connected to a start point of the winding of an (i+1)th upper coil, and 
 an end point of the winding of an i-th (where i=1 to N) lower coil is connected to a start point of the winding of an (i+1) lower coil, and 
 wherein a lower coil wire diameter is identical to an upper coil wire diameter. 
 
     
     
       2. The DC commutator motor according to  claim 1 , wherein
 the upper coil is constituted by a first continuous winding conductor, and 
 the lower coil is constituted by a second continuous winding conductor. 
 
     
     
       3. The DC commutator motor according to  claim 2 , wherein
 each of the plurality of commutator segments comprises a hook portion, the hook portion comprising a conductive member in a hook shape, 
 the end point of the winding of the i-th upper coil is hooked to the hook portion of one of the commutator segments to become the start point of the winding of the (i+1)th upper coil, the one of the commutator segments connecting the i-th upper coil and the (i+1)th upper coil, and 
 the end point of the winding of the i-th lower coil is hooked to the hook portion of one of the commutator segments to become the start point of the winding of the (i+1)th lower coil, the one of the commutator segments connecting the i-th lower coil and the (i+1)th lower coil. 
 
     
     
       4. The DC commutator motor according to  claim 3 , wherein
 the first winding conductor and the second winding conductor are constituted by one continuous winding conductor. 
 
     
     
       5. The DC commutator motor according to  claim 4 , wherein
 an external diameter of the armature is larger than an axial dimension of the armature. 
 
     
     
       6. A DC commutator motor comprising:
 a yoke; 
 a field magnet positioned at an inner peripheral side of the yoke; 
 an armature rotatably supported at an inner peripheral side of the field magnet with a gap therebetween; 
 a shaft positioned on a central axis of the armature; 
 a plurality of commutator segments positioned in a circumferential direction of the shaft; 
 a plurality of armature slots positioned on an outer periphery of the armature; 
 an upper coil wound the number of turns Na through two of the armature slots at an opening side of each of the two slots, the two of the armature slots being located apart from each other with the a predetermined number of armature slots therebetween; and 
 a lower coil connected in parallel with the upper coil, the lower coil being wound the number of turns Nb through the two of the armature slots at a bottom side of each of the two slots, 
 wherein the number of turns Na is smaller than the number of turns Nb, and the number of turns Na of the upper coil and the number of turns Nb of the lower coil are set such that a lower coil resistance value is higher than an upper coil resistance value, 
 wherein the number of turns Na of the upper coil and the number of turns Nb of the lower coil are set according to a difference between the lower coil resistance value and the upper coil resistance value, and 
 an end point of winding of an i-th (where i=1 to N) upper coil is connected to a start point of the winding of an (i+1)th upper coil, and 
 an end point of the winding of an i-th (where i=1 to N) lower coil is connected to a start point of the winding of an (i+1) lower coil, and 
 wherein a lower coil wire diameter is identical to an upper coil wire diameter. 
 
     
     
       7. A DC commutator motor comprising:
 a yoke; 
 a field magnet positioned at an inner peripheral side of the yoke; 
 an armature rotatably supported at an inner peripheral side of the field magnet with a gap therebetween; 
 a shaft positioned on a central axis of the armature; 
 a plurality of commutator segments positioned in a circumferential direction of the shaft; 
 a plurality of armature slots positioned on an outer periphery of the armature; 
 an upper coil wound the number of turns Na through two of the armature slots at an opening side of each of the two slots, the two of the armature slots being located apart from each other with the a predetermined number of armature slots therebetween; and 
 a lower coil connected in parallel with the upper coil, the lower coil being wound the number of turns Nb through the two of the armature slots at a bottom side of each of the two slots, 
 wherein the number of turns Na is smaller than the number of turns Nb, and the number of turns Na of the upper coil and the number of turns Nb of the lower coil are set such that a lower coil resistance value is higher than an upper coil resistance value, 
 wherein the sum of the number of turns Na and the number of turns Nb equals a sum value; 
 wherein a difference between the upper coil resistance value associated with the selected number of turns Na and the lower coil resistance value associated with the selected number of turns Nb is less than all possible differences in resistance values associated with other numbers of turns which have the same sum value, and 
 an end point of winding of an i-th (where i=1 to N) upper coil is connected to a start point of the winding of an (i+1)th upper coil, and 
 an end point of the winding of an i-th (where i=1 to N) lower coil is connected to a start point of the winding of an (i+1) lower coil, and 
 wherein a wire diameter of the upper coil is identical to a wire diameter of the lower coil.